S-RAID5：一种适用于顺序数据访问的节能磁盘阵列

S-RAID 5:An Energy-Saving RAID for Sequential Access Based Applications

磁盘及其冷却系统是现代存储系统中能耗的主体,已有的节能研究主要面向以随机数据访问为主的存储系统,对于广泛存在的以顺序数据访问为主的存储系统,如视频监控、虚拟磁带库(VTL)、连续数据保护(CDP)等,针对该类系统固有访问模式的节能研究较少.为此,提出了适用于顺序数据访问的节能磁盘阵列S-RAID 5,采用局部并行策略:阵列中的存储区被分成若干组,组内采用并行访问模式,分组有利于调度部分磁盘运行而其余磁盘待机,组内并行用以提供性能保证.在S-RAID 5磁盘阵列中运行磁盘调度算法,辅以合适的Cache策略来过滤少量的随机访问,S-RAID 5可获得显著的节能效果.在32路D1标准的视频监控模拟实验中,在满足性能需求、单盘容错的条件下,24小时功耗测量实验表明:S-RAID 5的功耗为节能磁盘阵列Hibernator功耗的59%,eRAID功耗的23%,PARAID、GRAID功耗的21%左右.

In modern-day storage systems, disk arrays and their cooling systems consume a major portion of total system power consumption. The existing research work on energy conservation mainly concentrates on optimizing the storage systems for random access-based applications. However, for the widely-used storage systems for sequential access-based applications, such as video surveillance, continuous data protection （CDP）, virtual tape library （VTL）, few schemes are proposed to gain better energy conservation according to their inherent characteristics with I/O performance guarantee so far. To this end, S-RAID 5, an energy-saving RAID system, is proposed for sequential access-based applications. In S-RAID 5, a local-parallelism strategy is employed, the entire storage area of the array is partitioned into different groups, and in each group a parallel data access scheme is adopted. Data grouping makes it possible to keep only a portion of disks active while keeping the rest standby. On the other hand, the intra-group paral- lelism is used to provide the performance guarantee. With an appropriate caching strategy to filter out a small amount of random accesses, S-RAID 5 can achieve prominent energy simulation experiment of 32-channel video surveillance with D1 resolution standard, ment results of 24-hour power consumption show that the power consumption of 59%, 23%, 21%, and 21% of those of Hibernator, eRAID, PARAID, and GRAID, while meeting the I/O performance and single-disk fault tolerance. saving. In a the measure- S-RAID 5 is respectively,